Alkoxypentadienoate polymer compositions



Patented July 28, 1953 UNITED STATES PATENT OFFICE;

ALKOXYPENTADIENOATE POLYMER COMPOSITIONS Vaughn A. Engelhardt, Wilmington, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 20, 1950, Serial No. 150,813

8 Claims. (Cl. 260-483) (CH=C(OCOCH3) CH=CH2) which can likewise be converted into a rubberlike polymer.

This invention has as an object the preparation of new ether esters. Another object is the preparation of new polymerizable monomers. A further object is the preparation of new polymers. Other objects will appear hereinafter.

These objects are accomplished by the present invention wherein vinylacetylene is reacted with the carbonate of hydrocarbon alcohol, ROH, wherein R is a monovalent hydrocarbon radical with its free valence stemming from carbon of aliphatic character, i. e., from non-aromatic carbon, in the presence of an alkaline catalyst to form new polymerizable ether esters of the formula CH2=CHC (OR) CHCOOR wherein the Rs are ordinarily the same and are monovalent hydrocarbon radicals with their free valence'stemming from carbon of aliphatic character. These compounds are esters of 2,4- pentadienoic acids having an ether substituent on the third carbon atom. Thus the product in which R is ethyl is ethyl 3-ethoxy-2,4-pentadienoate. I

The following examples in which parts are by weight are illustrative of the invention.

EXAMPLE I Fifty-one (51) parts of vinylacetylene was added portionwise during the course of 2.5 hours to a well-stirred mixture of approximately 360 parts of ethyl carbonate and 26 parts of sodium ethoxide maintained at 80 C. in a reactor provided with a reflux condenser. After all the vinylacetylene had been added, the mixture was kept at'70-80" C. for an'additional 7.5 hours; The reaction mixture was then cooled and neutralized with 114 parts of aqueous 21% acetic acid. The

aqueous layer was separated from the organic layer, extracted with ether. and the extracts added to the organic layer. The organic layer was dried over magnesium sulfate and subjected to distillation under reduced pressure in the presence of 0.1 part of hydroquinone. The principal fractions obtained were as follows:

Parts (a) 39 C./23 mm. 246 (b) 92-116 C./2.3 mm. 35.5 (a) 73-76 C./0.2 mm 29.6

Fraction (a) consisted of unreacted ethyl carbonate, fraction (b) of a mixture of ethyl 3-ethoxy- 2,4-pentadienoate and its alcohol addition product, C11H20O4 (ethyl 3,5-diethoxy-2-pentenoate), and fraction (0) of the pure alcohol addition product (11 1.4509).

Analysis Calculated for Gill-12004: C, 61.08%; H, 9.32%;

saponification equivalent, 216.

Found: C, 60.98%; H, 9.61%; saponification equivalent, 217.3, 218.2.

Fraction (b) was added to a mixture of 80 parts toluene, 0.1 part of hydroquinone, and 0.2 part of sodium bisulfate. On heating the mixture, alcohol and toluene distilled at 75l10 C. under atmospheric pressure. The residual oil was then quickly distilled under 3 mm. pressure. This dis tillate was redistilled through a small packed column to give 26.2 parts of ethyl 3-ethoxy-2,4- pentadienoate, B. P. 79-805 C./2.8 mm., 11 1.4819.

Analysis Calculated for CaHnOa: C. 63.51%; H, 8.29%;

saponification equivalent, 170.

Found: C, 63.26%; H, 8.47%; saponification equivalent, 169.5, 168.4.

On standing at room temperature, ethyl 3 ethoxy-2,4- pentadienoate polymerized to a'clear. colorless gel. It was found that polymerization of the pentadienoate could be prevented either by adding a few crystals of hydroquinone or by storage in Dry Ice.

EXAMPLE II Twenty-six (26) parts of vinylacetylene was added during the course of three hours to an agitated mixture of 156 parts of dimethyl carbonate and 11 parts of sodium methoxide maintained at -73 C. under an oxygen-free vinylacetylene pressure of 3 to 5 lb./in. above atmospheric. The reaction mixture was cooled to 15 C. and neutralized with the calculated amount of 20% acetic acid. The aqueous layer was separated from the organic layer, washed with about 40 parts of ether, and the ether extract was added to the organic layer. The organic layer was dried over magnesium sulfate containing hydroquinone, and was then distilled. After removal of the ether and unreacted dimethyl carbonate (105 parts), a fraction (23.4 parts) boiling at 70-120" C./-25 mm. was obtained. This fraction was mixed with 0.1 part hydroquinone, 0.4 part sodium bisulfate, and about '70 1 parts toluene. This mixture was distilled at atmospheric;pressure until most of the toluene and lower boiling material had been removed,:and was then-distilled under reduced pressure. "Theidistillate which consisted of 8.7 parts of colorless liquid boiling at 91-93 C./20.5 mm.,"-was methyl methoxy-2,4-pentadienoate. On redistillation over hydroquinone, the product boiled at.8989.5 C./19 mm. and had a refractive index"(n of 1.4949.

- Analysis -:mol;'wt.,.142. Found:= C, ,59.05%,-.58.97%; H, 7.37%, 7.33%;

-mol. wt., 130, 14:2,153.

On standing the'product polymerizes to a colorless-resin.

" EXAMPLE III EI'en partsof -ethyl .3=.ethoxy.-ZA-pentadienoate and-0.2 .part .of.-v alphaalpha -azobiseisobutryonitrilevwere dissolved in 20 parts of drybenzene and refiuxed..,for;2;1 hours. When solvent was removedat C./.0;3.mm., imparts-of a brittle colorless .polymer .were obtained. ".The polymer softened and melted at 120 C.,- and on cooling, formed a clear but brittle film.

EXAMPLE IV ExampleIII wasrepeated. except that 0.2 P .of benzoyl peroxidewas .usedas initiator in place of the azonitrile. A quantitative yield-offlacolorless, taffy-like polymer was obtained. This majterial'slowly'assumed the shape of the container in which it was placed.

An emulsionpolymerization was carried out by "mixing 10' parts of -ethyl 3'-ethoxy-2,4epenta- *dienoate with 30 parts of water, 0:2 part -of' po- 'tassium persulf-ate, and-0.05 part of sodium "bisulfitef-0z05 part of the-sodium salt-of sulfated Lorol (Clo-C18 alcohols), and 0.5 partof disodium phosphate. "The mixture was heated at 501C; for hours in. a; pressure bottle mounted in a tumbler shaker. The. ;emulsion-was then .coagulatedwby theadditionof alcohol andthe solid polymer was collected by filtration. The

polymer was Washed successively with water and OEt -CH2CH2 'EXAMPLEVI A solutioncontaining 40.0 D.arts chloroprene, 10.0 parts ethyl 8=ethoXy-2A-pentadienoate,.2.0 parts Nancy wood rosin, and 0.17 part dodecyl .mercaptan was emulsified at room temperature in a solutioncontaining 78.5 parts-water, 0.47.5

,part sodium hydroxide, 0.30 part Daxad .11

(formaldehyde/sodium naphthalene sulfonate condensation .product) and 0.3.0 -partpotassl-um persulfate. The emulsion was. stirred slowly. and heated under a blanketofnitrogen to a temperature of 40 C. After eight minutes at this temperature polymerization started as evidenced .by. a rise in thetemperature 10f the emulsion.

The polymerization was run for 1.2 hours-at. 40- 43 C. During thistime the specificzgravityof the polymer latexrose from 0,98 to.1.050. The polymerization was stopped at this point by addition of 7.5 parts .of =an-emu-lsion prepared by emulsifying a solution containing .04: part phenothiazine, 0.4. part'p-tertiarybu-tyl catechol, and 70.4 parts benzene in .azsolutien containing parts water, 1.2 partssodium Lorol sulfate, and 0.6 part Daxad l1.

.Coagulationiof. '21 parts of thepolymer latex in 15.8.. partstethanol. gave 4.! "parts .of .a colorless, elastic wproduct. Analyses zindicated :that :the :product oonta'lned.;35.8%-.ch1orine which correspondswto aLcopQlymercontaining. 5.-.-6.:molea;per :cent: ethyl '3r-ethoxy-2Aepentadienoate. :The copolymer was soluble in benzeneaandxchloroform.

The chloroprene/ethyl -3-eth0Xy-2,4-pentadienoate copolymer was more resistant toward heat and light than polychloroprene. Thus rayon fabric impregnated with the copolymer latex and heatedforone hour at Cpwas'only-slightly discolored and tendered-whereas rayon fabric treated with a polychloroprene I latex became brown and'noticeably tendered-under these conditions. (The-degree of tendering of the rayon is a measure of the amount of HCl evolved-when the'polymers'are' heated and thus gives a qualitative indication of the stability of the polymer toward heat.)

;Etayon fabricsaimpregnated with thecopqlyfmer latex were also less. discolored andless tendered after; exposure. to. ultraviolet. light than rayon fabrics impregnated owith .a :lpolychloro prenexlatex.

.,An aqueous nlixture containingAaoparts butadiene.. 10.0, parts .ethyl.- 3=ethoxy:2,4epentadienm ate, 75,-.o.;p arts-water. Odie-part sodium hydroxide,

2.0 parts oleic acid, 0.5 part"Daxad. 11, 0.5 part potassium persulfate, 0.075 part potassium ferricyanide, 1.0 part Nancy wood rosin-and 0.17 part dodecyl mercaptan was prepared and heated in a closed vessel for 16 hours at 40. C. A stable emulsion was obtained to which was added 6.5 parts of the emulsion containing phenothiazine and p.-tertiary butyl catechol described inExample vVI. The polymer was isolated by pouring the emulsion into 552 parts ethanol. vA gumlike product was obtained which was washed with water and ethanoland dried. Therewas thus obtained 30.0 parts of ethyl 3-ethoxy-2,4 penta-' dienoate/butadiene copolymer. Analyses indicated that the product contained 81.55% carbon and 10.50% hydrogen which corresponds to a copolymer containing 7-8 mole percent ethyl 3-ethoxy-2,4-pentadienoate. Thiszcopolymer was soluble in chloroform but insoluble in benzene. It Was a colorless, tack-free solid whichexhibit'ed elastic properties. f

v EXAMPLE VIII Asolution containing-4.3 parts chloroprene, 1.8 parts ethyl 3-ethoxy-2,4-pentadienoate, and 0.05 part alpha, alpha'-azobis(alpha,gamma-dimethylvaleronitrile) as polymerization initiator was heated under nitrogen at atmospheric pressure for hours at 48-52 C. A soft, elastic ethyl 3-ethoxy 2,4 pentadienoate/chloroprene copolymer was obtained which was washed thoroughly with methanol and dried. Analyses indicated that the product (4.8 parts) contained 29.75% chlorine which corresponds to a copolymer containing 16-17 mole per cent ethyl 3- ethoxy-2,4-pentadienoate. The product was insoluble in benzene and chloroform.

EXAMPLE IX A mixture of 10 parts ethyl 3-ethoxy-2,4- pentadienoate, 10 parts acrylonitrile, 4.4 parts benzene, and 0.2 part alpha, a1pha'-azobisisobutyronitrile was refluxed for 5.5 hours. The polymer solution was diluted with 22 additional parts of benzene, and was then poured into about 300 parts of petroleum ether. This caused 18.4 parts of a copolymer of ethyl 3-ethoxy-2A-pentadienoate and acrylonitrile to separate. The polymer softened in the range 125 to 135 C., and was soluble in benzene, dimethylformamide, hot xylene, and in a 1:1 mixture of warm benzene and chloroform. The polymer was readily pressed into clear films at 160 C. Analysis showed that the copolymer contained approximately 65.2% carbon and 7.2% hydrogen, which indicated the presence of about equal parts by weight of ethyl 3-ethoxy-2,4-pentadienoate and acrylonitrile.

In the preparation of the 3-ether substituted 2,4-pentadienoic acid esters of this invention any carbonic ester of formula (RO)2C=O, in which R is a monovaient hydrocarbon radical with the free valence stemming from carbon of aliphatic character may be used. Additional examples of such carbonates are propyl, butyl, cyclohexyl, n-decyl, and benzyl carbonates. The preferred carbonates are alkyl carbonates in which the alkyl group contains from one to four carbons.

The ratio of the carbonate to monovinylacetylene can be varied widely but, for best results, it is desirable to use at least one mole of the carbonate for each mole of vinylacetylene. The pressure at which the reaction is carried out is not critical but to prevent loss of vinylacetylene and to insure safety of operation it is preferred 6 to operateiat moderately'low pressures; e': g.," one to 1 five atmospheres. The reaction. :is conveniently carried out at 20 to 150 C.1and generally at 30 to C. Temperaturesoutside these ranges can be used, however. As already indicated alkaline catalysts are used, preferably alkali alkoxides,

such as sodium methoxide, sodium butoxide and the corresponding potassium compounds. Other catalysts which can be used are sodium monovinylacetylide, sodium hydride, triphenylmethyl sodium, sodium amide and quaternary ammonium alkoxides, such as benzyltrimethylammonium ethoxide. 1

indicated in Example I, the reaction of the carbonate'with vinylacetylene yields, in addition to the alkyl.3-a1koxy-zglrpentadienoate, an alcohol addition product of the pentadienoate. This product, which is an alkyl-3,5-dialkoxy-2-pen,- tenoate; loses alcohol on heating with mildly acidic agents, such as sodium bisulfate', .to' form the corresponding alkyl 3-alkoxy-2,4-penta'- dienoate.

The substituted 2,4-pentadienoic esters of this invention-are for the most part liquids at ordinary temperatures, and are soluble in ether, ethanol, ethyl acetate, and acetone. They are readily susceptible to polymerization and forthis reason are best stored at low temperatures or admixed with polymerization inhibitors. They also react with bromine and with aqueous potassium permanganate.

The ZA-pentadienoates can be polymerized by the methods known for the polymerization of vinyl compounds. Suitable polymerization initiators are organic peroxides, e. g., diethyl peroxide; persulfates, e. g., sodium and ammonium persulfate; and the azonitriles described in Hunt U. s. 2,471,959. In general, any compound capable of yielding unstable free-radicals can be used as a polymerization initiator. The pentadienoates can be polymerized alone or in admixture with other polymerizable compounds or with compounds susceptible to copolymerization. Examples of such compounds, in addition to those already mentioned, are acrylic and methacrylic esters, e. g., ethyl acrylate and methyl methacrylate; olefins, e. g., ethylene and styrene; vinyl esters, e. g., vinyl chloride, vinyl fluoride, and vinyl acetate; halogenated ethylenes, e. g., vinylidene chloride; fiuorinated ethylenes, e. g., chlorotrifluoroethylene and tetrafiuoroethylene; maleic and fumaric compounds, e. g., maleic anhydride and diethyl fumarate; unsaturated nitriles, such as acrylonitrile and methacrylonitrile; and other dienes, e. g., fluoroprene, isoprene, butadiene and ethoxyprene. The pentadienoates can be copolymerized with each other or with one or more of the above-mentioned monomers.

As indicated in Example V, the polymeric pentadienoates can be hydrolyzed to give polymers containing p-ketoester or fi-ketoacid groups. These hydrolyzed polymers form chelates with metals, e. g., on treatment with metallized dyes.

The polymers (including copolymers) of this invention are useful in making coating and molding compositions. They can also be used as rubber-substitutes. In these and other uses the polymers can be compounded with dyes, pigments, fillers, vulcanizing agents, plasticizers, antioxidants, and other polymers. The hydrolyzed copolymers have enhanced dye receptivity.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the 

1. A POLYMER OF AN ETHER ESTER OF 3-HYDROXY2,4-PENTADIENOIC ACID WHEREIN THE HYDROXYL AND CARBOXYL HYDROGENS OF THE ACID ARE EACH REPLACED BY A MONOVALENT HYDROCARBON RADICAL WITH ITS FREE VALENCE STEMMING FROM CARBON OF ALIPHATIC CHARACTER. 